"""
Face of a triangle mesh.

"""

from __future__ import absolute_import

from fabmetheus_utilities.geometry.geometry_utilities import evaluate
from fabmetheus_utilities import xml_simple_reader
from fabmetheus_utilities import xml_simple_writer
import cStringIO


__author__ = 'Enrique Perez (perez_enrique@yahoo.com)'
__credits__ = 'Art of Illusion <http://www.artofillusion.org/>'
__date__ = '$Date: 2008/02/05 $'
__license__ = 'GNU Affero General Public License http://www.gnu.org/licenses/agpl.html'


def addFaces(geometryOutput, faces):
	'Add the faces.'
	if geometryOutput.__class__ == list:
		for element in geometryOutput:
			addFaces(element, faces)
		return
	if geometryOutput.__class__ != dict:
		return
	for geometryOutputKey in geometryOutput.keys():
		geometryOutputValue = geometryOutput[geometryOutputKey]
		if geometryOutputKey == 'face':
			for face in geometryOutputValue:
				faces.append(face)
		else:
			addFaces(geometryOutputValue, faces)

def addGeometryList(elementNode, faces):
	"Add vertex elements to an xml element."
	for face in faces:
		faceElement = xml_simple_reader.ElementNode()
		face.addToAttributes( faceElement.attributes )
		faceElement.localName = 'face'
		faceElement.parentNode = elementNode
		elementNode.childNodes.append( faceElement )

def getCommonVertexIndex( edgeFirst, edgeSecond ):
	"Get the vertex index that both edges have in common."
	for edgeFirstVertexIndex in edgeFirst.vertexIndexes:
		if edgeFirstVertexIndex == edgeSecond.vertexIndexes[0] or edgeFirstVertexIndex == edgeSecond.vertexIndexes[1]:
			return edgeFirstVertexIndex
	print("Inconsistent GNU Triangulated Surface")
	print(edgeFirst)
	print(edgeSecond)
	return 0

def getFaces(geometryOutput):
	'Get the faces.'
	faces = []
	addFaces(geometryOutput, faces)
	return faces

def processElementNode(elementNode):
	"Process the xml element."
	face = Face()
	face.index = len(elementNode.parentNode.xmlObject.faces)
	for vertexIndexIndex in xrange(3):
		face.vertexIndexes.append(evaluate.getEvaluatedInt(None, elementNode, 'vertex' + str(vertexIndexIndex)))
	elementNode.parentNode.xmlObject.faces.append(face)


class Edge(object):
	"An edge of a triangle mesh."
	def __init__(self):
		"Set the face indexes to None."
		self.faceIndexes = []
		self.vertexIndexes = []
		self.zMaximum = None
		self.zMinimum = None
	
	def __repr__(self):
		"Get the string representation of this Edge."
		return str( self.index ) + ' ' + str( self.faceIndexes ) + ' ' + str(self.vertexIndexes)

	def addFaceIndex( self, faceIndex ):
		"Add first None face index to input face index."
		self.faceIndexes.append( faceIndex )

	def getFromVertexIndexes( self, edgeIndex, vertexIndexes ):
		"Initialize from two vertex indices."
		self.index = edgeIndex
		self.vertexIndexes = vertexIndexes[:]
		self.vertexIndexes.sort()
		return self


class Face(object):
	"A face of a triangle mesh."
	def __init__(self):
		"Initialize."
		self.edgeIndexes = []
		self.index = None
		self.vertexIndexes = []

	def __repr__(self):
		"Get the string representation of this object info."
		output = cStringIO.StringIO()
		self.addXML( 2, output )
		return output.getvalue()

	def addToAttributes(self, attributes):
		"Add to the attribute dictionary."
		for vertexIndexIndex in xrange(len(self.vertexIndexes)):
			vertexIndex = self.vertexIndexes[vertexIndexIndex]
			attributes['vertex' + str(vertexIndexIndex)] = str(vertexIndex)

	def addXML(self, depth, output):
		"Add the xml for this object."
		attributes = {}
		self.addToAttributes(attributes)
		xml_simple_writer.addClosedXMLTag( attributes, depth, 'face', output )

	def copy(self):
		'Get the copy of this face.'
		faceCopy = Face()
		faceCopy.edgeIndexes = self.edgeIndexes[:]
		faceCopy.index = self.index
		faceCopy.vertexIndexes = self.vertexIndexes[:]
		return faceCopy

	def getFromEdgeIndexes( self, edgeIndexes, edges, faceIndex ):
		"Initialize from edge indices."
		if len(self.vertexIndexes) > 0:
			return
		self.index = faceIndex
		self.edgeIndexes = edgeIndexes
		for edgeIndex in edgeIndexes:
			edges[ edgeIndex ].addFaceIndex( faceIndex )
		for triangleIndex in xrange(3):
			indexFirst = ( 3 - triangleIndex ) % 3
			indexSecond = ( 4 - triangleIndex ) % 3
			self.vertexIndexes.append( getCommonVertexIndex( edges[ edgeIndexes[ indexFirst ] ], edges[ edgeIndexes[ indexSecond ] ] ) )
		return self

	def setEdgeIndexesToVertexIndexes( self, edges, edgeTable ):
		"Set the edge indexes to the vertex indexes."
		if len(self.edgeIndexes) > 0:
			return
		for triangleIndex in xrange(3):
			indexFirst = ( 3 - triangleIndex ) % 3
			indexSecond = ( 4 - triangleIndex ) % 3
			vertexIndexFirst = self.vertexIndexes[ indexFirst ]
			vertexIndexSecond = self.vertexIndexes[ indexSecond ]
			vertexIndexPair = [ vertexIndexFirst, vertexIndexSecond ]
			vertexIndexPair.sort()
			edgeIndex = len( edges )
			if str( vertexIndexPair ) in edgeTable:
				edgeIndex = edgeTable[ str( vertexIndexPair ) ]
			else:
				edgeTable[ str( vertexIndexPair ) ] = edgeIndex
				edge = Edge().getFromVertexIndexes( edgeIndex, vertexIndexPair )
				edges.append( edge )
			edges[ edgeIndex ].addFaceIndex( self.index )
			self.edgeIndexes.append( edgeIndex )
